Recently, a variety of electronic devices, such as a tablet type computer, a personal digital assistant (PDA), and a smartphone, have been developed. Most electronic devices of this type include a touch screen display so as to facilitate user's input operation.
By touching menus or objects, which are displayed on a touch screen display, with a pen or his/her finger, a user can instruct a portable electronic device to perform functions associated with the menus or the objects. Also, by handwriting characters or figures with a pen on a touch screen display, a user can input stroke data of the handwritten characters or figures.